Low-Gradient Aortic Stenosis With Preserved LVEF

Study Questions:

What are the mortality implications and what is the survival impact of aortic valve replacement (AVR) among patients with low-gradient (LG) aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF)?

Methods:

A meta-analysis was performed using studies published between 2005 and 2015 that addressed mortality in patients with LG AS and preserved LVEF, including paradoxical low-flow (i.e., stroke volume index <35 ml/m2) LG (LF-LG) and normal-flow (NF-LG), and those with high-gradient (≥40 mm Hg) AS or moderate AS. The primary outcome was survival benefit associated with AVR. A secondary outcome measure was overall mortality regardless of treatment.

Results:

A total of 18 studies were included in the analysis. Patients with LF-LG AS had increased mortality compared with patients with moderate AS (hazard ratio [HR], 1.68; 95% confidence interval [CI], 1.31-2.17), NF-LG (HR, 1.80; 95% CI, 1.29-2.51), and high-gradient AS (HR, 1.67; 95% CI, 1.16-2.39) AS. AVR was associated with reduced mortality in patients with LF-LG (HR, 0.44; 95% CI, 0.25-0.77). A similar benefit occurred with AVR in patients with NF-LG (HR, 0.48; 95% CI, 0.28-0.83). Compared to patients with high-gradient AS, those with LF-LG were less likely to be referred to AVR (odds ratio, 0.32; 95% CI, 0.21-0.49).

Conclusions:

Patients with paradoxical LF-LG AS and NF-LG AS have increased risk of mortality compared with other subtypes of AS with preserved LVEF, and improved outcome with AVR.

Perspective:

Debate continues regarding the clinical impact of LF-LG AS with preserved LVEF. Clinical confounders include concern that measurement error could incorrectly establish a diagnosis of LF-LG severe AS, and that ‘low-flow’ AS could be incorrectly diagnosed without documentation of LF (stroke volume index <35 ml/m2). Using available literature in a meta-analysis, this study provides further support that patients with true LG severe AS (with either LF or NF) are at increased mortality risk, and have improved outcomes associated with AVR.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and CHD & Pediatrics, Cardiac Surgery and VHD, Congenital Heart Disease, CHD & Pediatrics and Imaging, CHD & Pediatrics and Interventions, CHD & Pediatrics and Quality Improvement, Interventions and Imaging, Interventions and Structural Heart Disease

Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Diagnostic Imaging, Heart Defects, Congenital, Heart Valve Diseases, Heart Valve Prosthesis, Mortality, Outcome Assessment (Health Care), Stroke Volume, Survival, Ventricular Function, Left


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